BACKGROUND: Triple-negative breast cancer (TNBC) is recognized as the most aggressive and immunologically infiltrated subtype of breast cancer. A high circulating neutrophil-to-lymphocyte ratio (NLR) is strongly linked to a poor prognosis among patients with breast cancer, emphasizing the critical role of neutrophils. Although the involvement of neutrophils in tumor metastasis is well documented, their interactions with primary tumors and tumor cells are not yet fully understood.
METHODS: Clinical data were analyzed to investigate the role of neutrophils in breast cancer. In vivo mouse model and in vitro co-culture system were used for mechanism researches. Blocking experiments were further performed to identify therapeutic agents against TNBC.
RESULTS: TNBC cells secreted GM-CSF to sustain the survival of mature neutrophils and upregulated CD11b expression. Through CD11b, neutrophils specifically binded to ICAM1 on TNBC cells, facilitating adhesion. Transcriptomic sequencing combined with human and murine functional experiments revealed that neutrophils, through direct CD11b-ICAM1 interactions, activated the MAPK signaling pathway in TNBC cells, thereby enhancing tumor cell invasion and migration. Atorvastatin effectively inhibited ICAM1 expression in tumor cells, and tumor cells with ICAM1 knockout or treated with atorvastatin were unresponsive to neutrophil activation. The MAPK pathway and MMP9 expression were significantly inhibited in the tumor tissues of TNBC patients treated with atorvastatin.
CONCLUSIONS: Targeting CD11b-ICAM1 with atorvastatin represented a potential clinical approach to reduce the malignant characteristics of TNBC.

OBJECTIVE: In gout, monosodium urate crystals are taken up by macrophages, triggering the activation of the NLRP3 inflammasome and the maturation of IL-1β. This study aimed to investigate the role of integrin CD11b in inflammasome activation in macrophages stimulated by MSU.
METHODS: BMDM from WT and CD11b KO mice were stimulated in vitro with MSU crystals. Cellular supernatants were collected to assess the expression of the inflammatory cytokines by enzyme-linked immunosorbent assay and western blot methods. The role of integrin CD11b in MSU-induced gouty arthritis in vivo was investigated by intra-articular injection of MSU crystals. Real-time extracellular acidification rate and oxygen consumption rate of BMDMs were measured by Seahorse Extracellular Flux Analyzer.
RESULTS: We demonstrate that CD11b-deficient mice developed exacerbated gouty arthritis with increased recruitment of leukocytes in the joint and higher IL-1β levels in the sera. In macrophages, genetic deletion of CD11b induced a shift of macrophage metabolism from oxidative phosphorylation to glycolysis, thus decreasing the overall generation of intracellular ATP. Upon MSU stimulation, CD11b-deficient macrophages showed an exacerbated secretion of IL-1β. Treating wild-type macrophages with a CD11b agonist, LA1, inhibited MSU-induced release of IL-1β in vitro and attenuated the severity of experimental gouty arthritis. Importantly, LA1, was also effective in human cells as it inhibited MSU-induced release of IL-1β by peripheral blood mononuclear cells from healthy donors.
CONCLUSIONS: Our data identified the CD11b integrin as a principal cell membrane receptor that modulates NLRP3 inflammasome activation by MSU crystal in macrophages, which could be a potential therapeutic target to treat gouty arthritis in human patients.

Cumulative evidence has established that Interferon (IFN)-γ has both pathogenic and protective roles in Multiple Sclerosis and the animal model, Experimental Autoimmune Encephalomyelitis (EAE). However, the underlying mechanisms to the beneficial effects of IFN-γ are not well understood. In this study, we found that IFN-γ exerts therapeutic effects on chronic, relapsing-remitting, and chronic progressive EAE models. The frequency of regulatory T (Treg) cells in spinal cords from chronic EAE mice treated with IFN-γ was significantly increased with no effect on Th1 and Th17 cells. Consistently, depletion of FOXP3-expressing cells blocked the protective effects of IFN-γ, indicating that the therapeutic effect of IFN-γ depends on the presence of Treg cells. However, IFN-γ did not trigger direct in vitro differentiation of Treg cells. In vivo administration of blocking antibodies against either interleukin (IL)-10, transforming growth factor (TGF)-β or program death (PD)-1, revealed that the protective effects of IFN-γ in EAE were also dependent on TGF-β and PD-1, but not on IL-10, suggesting that IFN-γ might have an indirect role on Treg cells acting through antigen-presenting cells. Indeed, IFN-γ treatment increased the frequency of a subset of splenic CD11b+ myeloid cells expressing TGF-β-Latency Associated Peptide (LAP) and program death ligand 1 (PD-L1) in a signal transducer and activator of transcription (STAT)-1-dependent manner. Furthermore, splenic CD11b+ cells from EAE mice preconditioned in vitro with IFN-γ and myelin oligodendrocyte glycoprotein (MOG) peptide exhibited a tolerogenic phenotype with the capability to induce conversion of naïve CD4+ T cells mediated by secretion of TGF-β. Remarkably, adoptive transfer of splenic CD11b+ cells from IFN-γ-treated EAE mice into untreated recipient mice ameliorated clinical symptoms of EAE and limited central nervous system infiltration of mononuclear cells and effector helper T cells. These results reveal a novel cellular and molecular mechanism whereby IFN-γ promotes beneficial effects in EAE by endowing splenic CD11b+ myeloid cells with tolerogenic and therapeutic activities.

Typical BCR::ABL1-negative myeloproliferative neoplasms (MPN) are mainly referred to as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofbrosis (PMF). Granulocytes in MPN patients are involved in their inflammation and form an important part of the pathophysiology of MPN patients. It has been shown that the immunophenotype of granulocytes in MPN patients is altered. We used flow cytometry to explore the immunophenotype of MPN patients and correlate it with clinical parameters. The results showed that PMF patients and PV patients had higher CD15+CD11b+ granulocytes than ET patients and normal controls. When grouped by gene mutation, changes in the granulocyte immunophenotype of MPN patients were independent of the JAK2V617F and CALR mutations. There was no significant heterogeneity in immunophenotype between ET patients and Pre-PMF, and between Overt-PMF and Pre-PMF patients. Granulocytes from some MPN patients showed an abnormal CD13/CD16 phenotype with a significant increase in mature granulocytes on molecular and cytomorphological grounds, and this abnormal pattern occurred significantly more frequently in PMF patients than in ET patients. CD15-CD11b- was negatively correlated with WBC and Hb and positively correlated with DIPSS score, whereas high CD10+ granulocytes were significantly and negatively associated with prognostic system IPSS and DIPSS scores in PMF patients. In conclusion, this study demonstrates the landscape of bone marrow granulocyte immunophenotypes in MPN patients. MPN patients, especially those with PMF, have a significant granulocyte developmental overmaturation phenotype. CD10+ granulocytes may be involved in the prognosis of PMF patients.

BACKGROUND: We aimed to elucidate the inflammatory response of Aspergillus fumigatus conidia in a whole-blood model of innate immune activation and to compare it with the well-characterized inflammatory reaction to Escherichia coli.
METHODS: Employing a human lepirudin whole-blood model, we analyzed complement and leukocyte activation by measuring the sC5b-9 complex and assessing CD11b expression. A 27-multiplex system was used for quantification of cytokines. Selective cell removal from whole blood and inhibition of C3, C5, and CD14 were also applied.
RESULTS: Our findings demonstrated a marked elevation in sC5b-9 and CD11b post-A. fumigatus incubation. Thirteen cytokines (TNF, IL-1β, IL-1ra, IL-4, IL-6, IL-8, IL-17, IFNγ, MCP-1, MIP-1α, MIP-1β, FGF-basic, and G-CSF) showed increased levels. A generally lower level of cytokine release and CD11b expression was observed with A. fumigatus conidia than with E. coli. Notably, monocytes were instrumental in releasing all cytokines except MCP-1. IL-1ra was found to be both monocyte and granulocyte-dependent. Pre-inhibiting with C3 and CD14 inhibitors resulted in decreased release patterns for six cytokines (TNF, IL-1β, IL-6, IL-8, MIP-1α, and MIP-1β), with minimal effects by C5-inhibition.
CONCLUSIONS: A. fumigatus conidia induced complement activation comparable to E. coli, whereas CD11b expression and cytokine release were lower, underscoring distinct inflammatory responses between these pathogens. Complement C3 inhibition attenuated cytokine release indicating a C3-level role of complement in A. fumigatus immunity.

Paraquat (PQ) exposure is strongly associated with neurotoxicity. However, research on the neurotoxicity mechanisms of PQ varies in terms of endpoints of toxic assessment, resulting in a great challenge to understand the early neurotoxic effects of PQ. In this study, we developed an adverse outcome pathway (AOP) to investigate PQ-induced neuro-immunotoxicity from an immunological perspective, combining of traditional toxicology methods and computer simulations. In vivo, PQ can microstructurally lead to an early synaptic loss in the brain mice, which is a large degree regarded as a main reason for cognitive impairment to mice behavior. Both in vitro and in vivo demonstrated synapse loss is caused by excessive activation of the complement C1q/C3-CD11b pathway, which mediates microglial phagocytosis dysfunction. Additionally, the interaction between PQ and C1q was validated by molecular simulation docking. Our findings extend the AOP framework related to PQ neurotoxicity from a neuro-immunotoxic perspective, highlighting C1q activation as the initiating event for PQ-induced neuro-immunotoxicity. In addition, downstream complement cascades induce abnormal microglial phagocytosis, resulting in reduced synaptic density and subsequent non-motor dysfunction. These findings deepen our understanding of neurotoxicity and provide a theoretical basis for ecological risk assessment of PQ.

UNASSIGNED: A growing body of evidence has shown that activating spinal cord glial cells (typically astrocytes and microglial cells) is closely related to hyperpathia and persistent pain.
UNASSIGNED: To investigate the expression of GFAP and CR3/CD11b in cornu dorsale medullae spinalis of rats with nonbacterial prostatitis, to explore the therapeutic efficacy and action mechanism of intrathecal injection of BNP alleviating chronic neuropathic pain.
UNASSIGNED: Eighteen male SPF SD rats were randomly divided into sham operation control group, nonbacterial prostatitis group (NBP) and intrathecal injection BNP group, the NBP model was established by intraprostatic injection of CFA, and the spinal cord of L6-S1 segment was extracted seven days after intrathecal injection of BNP; The expression of GFAP and CR3/CD11b in dorsal horn of spinal cord were detected by immunofluorescence and Western blot.
UNASSIGNED: The cumulative optical density values of GFAP and CR3/CD11b immunofluorescence assay in the NBP group were higher than those in the sham operation group, with statistical significance (p⁢ï⁢¼⁢ 0.01); The expression of GFAP and CR3/CD11b in intrathecal injection BNP group were lower than those in NBP group, the differences were statistically significant (p⁢ï⁢¼⁢ 0.01). Western blot results showed that the expression of GFAP and CR3/CD11B in NBP group were higher than those in sham operation group, with statistical significance (p⁢ï⁢¼⁢ 0.05). The expression of GFAP and CR3/CD11B in intrathecal injection BNP group were lower than those in NBP group, the differences were statistically significant (p⁢ï⁢¼⁢ 0.05).
UNASSIGNED: Intrathecal injection of BNP can down-regulate the expressions of GFAP and CR3/CD11b in L6-S1 spinal cord of NBP rat model and to further inhibit chronic pain caused by NBP.

Higher intensity exercise, despite causing more tissue damage, improved aging conditions. We previously observed decreased p16INK4a mRNA in human skeletal muscle after high-intensity interval exercise (HIIE), with no change following equivalent work in moderate-intensity continuous exercise. This raises the question of whether the observed senolytic effect of exercise is mediated by inflammation, an immune response induced by muscle damage. In this study, inflammation was blocked using a multiple dose of ibuprofen (total dose: 1200 mg), a commonly consumed nonsteroidal anti-inflammatory drug (NSAID), in a placebo-controlled, counterbalanced crossover trial. Twelve men aged 20-26 consumed ibuprofen or placebo before and after HIIE at 120% maximum aerobic power. Multiple muscle biopsies were taken for tissue analysis before and after HIIE. p16INK4a+ cells were located surrounding myofibers in muscle tissues. The maximum decrease in p16INK4a mRNA levels within muscle tissues occurred at 3 h post-exercise (-82%, p < 0.01), gradually recovering over the next 3-24 h. A concurrent reduction pattern in CD11b mRNA (-87%, p < 0.01) was also found within the same time frame. Ibuprofen treatment attenuated the post-exercise reduction in both p16INK4a mRNA and CD11b mRNA. The strong correlation (r = 0.88, p < 0.01) between p16INK4a mRNA and CD11b mRNA in muscle tissues suggests a connection between the markers of tissue aging and pro-inflammatory myeloid differentiation. In conclusion, our results suggest that the senolytic effect of high-intensity exercise on human skeletal muscle is mediated by acute inflammation.

BACKGROUND: The liver regeneration is a highly complicated process depending on the close cooperations between the hepatocytes and non-parenchymal cells involving various inflammatory cells. Here, we explored the role of myeloid-derived suppressor cells (MDSCs) in the processes of liver regeneration and liver fibrosis after liver injury.
METHODS: We established four liver injury models of mice including CCl4-induced liver injury model, bile duct ligation (BDL) model, concanavalin A (Con A)-induced hepatitis model, and lipopolysaccharide (LPS)-induced hepatitis model. The intrahepatic levels of MDSCs (CD11b+Gr-1+) after the liver injury were detected by flow cytometry. The effects of MDSCs on liver tissues were analyzed in the transwell co-culture system, in which the MDSCs cytokines including IL-10, VEGF, and TGF-β were measured by ELISA assay and followed by being blocked with specific antibodies.
RESULTS: The intrahepatic infiltrations of MDSCs with surface marker of CD11b+Gr-1+ remarkably increased after the establishment of four liver injury models. The blood served as the primary reservoir for hepatic recruitment of MDSCs during the liver injury, while the bone marrow appeared play a compensated role in increasing the number of MDSCs at the late stage of the inflammation. The recruited MDSCs in injured liver were mainly the M-MDSCs (CD11b+Ly6G-Ly6Chigh) featured by high expression levels of cytokines including IL-10, VEGF, and TGF-β. Co-culture of the liver tissues with MDSCs significantly promoted the proliferation of both hepatocytes and hepatic stellate cells (HSCs).
CONCLUSIONS: The dramatically and quickly infiltrated CD11b+Gr-1+ MDSCs in injured liver not only exerted pro-proliferative effects on hepatocytes, but also accounted for the activation of profibrotic HSCs.

Differentiation therapy using all-trans retinoic acid (ATRA) for acute promyelocytic leukemia (APL) is well established. However, because the narrow application and tolerance development of ATRA need to be improved, we searched for another efficient myeloid differentiation inducer. Kinase activation is involved in leukemia biology and differentiation block. To identify novel myeloid differentiation inducers, we used a Kinase Inhibitor Screening Library. Using a nitroblue tetrazolium dye reduction assay and real-time quantitative PCR using NB4 APL cells, we revealed that, PD169316, SB203580, SB202190 (p38 MAPK inhibitor), and triciribine (TCN) (Akt inhibitor) potently increased the expression of CD11b. We focused on TCN because it was reported to be well tolerated by patients with advanced hematological malignancies. Nuclear/cytoplasmic (N/C) ratio was significantly decreased, and myelomonocytic markers (CD11b and CD11c) were potently induced by TCN in both NB4 and acute myeloid leukemia (AML) M2 derived HL-60 cells. Western blot analysis using NB4 cells demonstrated that TCN promoted ERK1/2 phosphorylation, whereas p38 MAPK phosphorylation was not affected, suggesting that activation of the ERK pathway is involved in TCN-induced differentiation. We further examined that whether ATRA may affect phosphorylation of ERK and p38, and found that there was no obvious effect, suggesting that ATRA induced differentiation is different from TCN effect. To reveal the molecular mechanisms involved in TCN-induced differentiation, we performed microarray analysis. Pathway analysis using DAVID software indicated that \"hematopoietic cell lineage\" and \"cytokine-cytokine receptor interaction\" pathways were enriched with high significance. Real-time PCR analysis demonstrated that components of these pathways including IL1β, CD3D, IL5RA, ITGA6, CD44, ITGA2B, CD37, CD9, CSF2RA, and IL3RA, were upregulated by TCN-induced differentiation. Collectively, we identified TCN as a novel myeloid cell differentiation inducer, and trials of TCN for APL and non-APL leukemia are worthy of exploration in the future.